贵州晴隆锑矿床成矿流体He-Ar同位素地球化学  

He and Ar isotope geochemistry of ore-forming fluids for the Qinglong Sb deposit in Guizhou Province,China

作　　者：陈娴[1,2] 苏文超[1] 黄勇[1,2] 

机构地区：[1]中国科学院地球化学研究所,矿床地球化学国家重点实验室,贵阳550081 [2]中国科学院大学,北京100049

出　　处：《岩石学报》2016年第11期3312-3320,共9页Acta Petrologica Sinica

基　　金：国家自然科学基金重点项目(41230316);国家“973”项目(2014CB440906、2014CB440904)联合资助

摘　　要：晴隆锑矿床是华南中生代低温成矿域右江盆地Au-Sb-As-Hg矿集区内的大型锑矿床,成矿时代约150Ma。本文以该矿床矿石矿物辉锑矿中的流体包裹体为测试对象,研究了成矿流体的He和Ar同位素地球化学。研究表明,成矿流体的~3He/~4He为0.13~0.46Ra(Ra为空气的3He/4He值,1.4×10^(-6)),^(40)Ar/^(36)Ar为305~327,He、Ar同位素组成具有一定程度的正相关;成矿流体由两个端元组成:一是含地壳He的低温饱和空气的雨水,二是含地幔He的高温流体。含地幔He的高温流体可能来自右江盆地下部的侏罗纪壳幔混合成因花岗岩浆,这种岩浆的形成机制与华夏地块侏罗纪与钨锡成矿有关的花岗岩具有相似性。晴隆锑矿床以大气降水为主的成矿流体的加热、循环并浸取矿床围岩"大厂层"下伏地层中的成矿元素而成矿,受深部壳幔混合成因花岗岩浆释放出的含幔源He和岩浆S的热流所驱动。The Qinglong Sb deposit locates within the Youjiang Au-Sb-As-Hg metallogenic province in South China low-temperature metallogenic domain. This paper reports He and Ar isotopic data of fluid inclusions trapped by stibnites from the Qinglong Sb deposit with age of about 150Ma. 3He/4He ratios range from 0. 13 to 0.46Ra（where Ra is the 3He/4Heratio of air = 1.4 × 10^-6） , and 40Ar/36Ar from 305 to 327. Moreover, there are some positive correlations between He and Ar isotopic compositions. The results suggest that the ore-forming fluids are a mixture between a crustal fluid containing atmospheric Ar and crustal 4He and a fluid containing mantle components. It is likely that the former is a low temperature meteoric fluid, and the later is a fluid exsolved from a concealed Jurassic granitic magma, which might be formed by crustal melting induced by intrusion of a mantle-derived magma, similar to the contemporaneous W-Sn deposits-related granites in the Cathaysian Block of South China. The Jurassic deep-seated magma triggered the fluids of possibly meteoric origin to circulate and leach out ore-forming elements from sedimentary rocks underlain by the wallrock ＂Dachang Formation＂ of the deposit to form the Qinglong Sb deposit.

关 键 词：晴隆锑矿床 辉锑矿 流体包裹体 He和Ar同位素 幔源He 

分 类 号：P595[天文地球—地球化学] P618.66[天文地球—地质学]